This invention relates to a method for determining specific material characteristics of plastics.
A method of this type is disclosed, for example, in U.S. Pat. No. 4,568,874, which relates to the non-invasive measurement of material, for example a plastic material, with an electrical field. In the known method, three electrodes are necessary, two electrodes being configured as measuring electrodes. An additional electrode serves for shielding for the two measuring electrodes. It is also known to provide a shunt electrode instead of an electrode for shielding. With such a shunt electrode, a compensation of certain material properties is achieved. A disadvantage of the known system is, however, that the sensor technology is quite complicated and is hampered by a high uncertainty factor.